The noncooperative games discussed in Chap. 2 fail to reflect all the facets of optimal behavior in n-person market games. In particular, equilibria in noncooperative games do not take into consideration Pareto efficiency or group optimality. Chapter 3 considers cooperation in economic optimization and it is shown that group optimality and individual rationality are two essential properties for cooperation. However, merely satisfying group optimality and individual rationality does not necessarily bring about a dynamically stable solution in economic cooperation because there is no guarantee that the agreed-upon optimality principle is fulfilled throughout the cooperative period. In this chapter we consider dynamically stable economic optimization.